Partial derivatives/ total derivative

1. The problem statement, all variables and given/known data
I've attactched an image of the question, I hope this is ok, if not let me know and I'll copy it out onto a post,

3. The attempt at a solution
I've done parts (a) and (b) using the total derivative of f ( http://mathworld.wolfram.com/TotalDerivative.html ) but I can't get started on the last part. I've tried differentiating the expressions found in (a) but it doesn't seem to lead anywhere.

You have the definitions. All I can say is "just do it"! You are asked to show that
[tex]\frac{\partial f}{\partial x}= u\frac{\partial F}{\partial u}+ v\frac{\partial F}{\partial v}[/tex]
u= excos(y), v= exsin(y) and F(u,v)= f(x,y).

Thanks for the reply: I've done parts (a) and (b) already, it's the third part I'm struggling with (I can't quite see how your post relates to this bit). I won't post my solutions for these bits unless thay would be helpful, since they are show that... questions.